Overhearers Use Addressee Backchannels in Dialog Comprehension

Observing others in conversation is a common format for comprehending language, yet little work has been done to understand dialog comprehension. We tested whether overhearers use addressee backchannels as predictive cues for how to integrate information across speaker turns during comprehension of spontaneously produced collaborative narration. In Experiment 1, words that followed specific backchannels (e.g., really, oh) were recognized more slowly than words that followed either generic backchannels (e.g., uh huh, mhm) or pauses. In Experiment 2, we found that when the turn after the backchannel was a continuation of the narrative, specific backchannels prompted the fastest verification of prior information. When the turn after was an elaboration, they prompted the slowest, indicating that overhearers took specific backchannels as cues to integrate preceding talk with subsequent talk. These findings demonstrate that overhearers capitalize on the predictive relationship between backchannels and the development of speakers' talk, coordinating information across conversational roles.